High-performance ammonia gas sensor based on three-dimensional interconnected CNT/PANI/SiNW

The detection of ammonia at trace levels is helpful for tracing pollution sources in air pollution control and identifying early-stage diseases, thereby offering practical value in environmental monitoring and medical diagnosis. Although carbon nanotube/polyaniline (CNT/PANI) composites exhibit good response toward NH3, they tend to suffer from serious agglomeration during the growth process. In this work, we modified the three-dimensional structure of the substrate and successfully prepared the CNT/PANI/silicon nanowire (SiNW) ammonia gas sensor. Material characterizations confirmed that the SiNW significantly improved the dispersion of CNTs/PANI composites. Subsequently, the sensor exhibited a response amplitude of 112.8% at 1 ppm NH3 and 260.5% at 10 ppm at room temperature, which surpassed most other similar polymer-based sensors. Furthermore, the sensor exhibited a detection limit as low as 1 ppb, which is approximately one order of magnitude lower than that of most existing sensors. The results also demonstrated that the sensor possessed a fast response time and high selectivity toward NH3 detection.